A recent copying machine is designed to be used in combination with an automatic document transporting device and a sheet post-processing device for realizing automation of a copying operation, and automation of a post process performed with respect to copied sheets.
Here, the sheet post-processing device is to perform a post process (a stapling process and a punching process) with respect to a predetermined number of sheets, which were discharged from a copying machine.
In the sheet post-processing device, a predetermined number of the sheets are stacked as a sheet bundle on a post-processing tray. Further, after the post process such as the stapling process is performed with respect to the sheet bundle, the sheet bundle is discharged to a discharge tray.
However, upon transportation of sheets, there is a case where the sheets jam in a transport path of the sheet post-processing device. Thus, the transport path which cannot be opened causes such inconvenience that it is difficult to remove the jamming sheets (jam-disposal) from the transport path.
Thus, as to the sheet post-processing device, some techniques, which makes the jam-disposal easier, has been being developed conventionally.
For example, a document {circle around (1)}: Japanese Unexamined Patent Publication No. 129920/1998 (Tokukaihei 10-129920) (publication date: May 19, 1998) discloses a sheet post-processing device in which a staple unit can be drawn from a main body of the device.
The staple unit includes a staple tray (post-processing tray) and a stapler. Thus, when the unit is drawn, it is possible to perform the jam-disposal, with nothing above the staple tray. Further, it is possible to remove jamming staples and to supply staples efficiently.
Further, a document {circle around (2)}: Japanese Unexamined Patent Publication No. 143158/1999 (Tokukaihei 11-143158, corresponding to U.S. application Ser. Nos. 09/189,546 and 09/875,492)(publication date: May 28, 1999) discloses a sheet post-processing device in which it is possible to form a space above a staple tray.
That is, the device is arranged so that a sheet guide provided above the staple tray can be moved in the device. Further, this guide is moved in a direction away from the staple tray, so that it is possible to form an operating space (space for the jam-disposal), which is so wide that the jam-disposal can be performed, above the staple tray. Thus, an operator can insert his/her hand into the device so as to perform the jam-disposal above the staple tray.
However, the foregoing prior arts bear the following problems. That is, in the device of the document {circle around (1)}, the unit including the staple tray is moved in performing the jam-disposal, so that the consistency of the sheet bundle which is stacked on the tray is lost (when the staple tray moves and stops, the bundle moves in a moving direction of the tray due to inertial force).
Thus, the device bears a problem that the stapling process is not performed completely after the jam-disposal is performed.
Note that, the device has a jogger above the staple tray so as to keep the consistency of the bundle. However, the jogger can move parallel to a moving direction of the tray. Thus, when the staple tray moves and stops, the jogger also moves with the movement of the sheet bundle in the moving direction of the tray, so that it is impossible to keep the consistency of the sheet bundle.
Furthermore, even when the sheet bundle is made consistent again by the jogger after the staple tray is returned in the device, it is difficult to obtain the original consistency again (particularly, when the entire sheets move, it is so difficult to restore the consistency).
Furthermore, the device of the document {circle around (2)} is arranged so that an operating space is formed in the device by moving the sheet guide. Thus, it is required that a space for moving the sheet guide and a space used as the operating space are provided in advance, so that the device is bulky.